1 /* 2 * "LAPB via ethernet" driver release 001 3 * 4 * This code REQUIRES 2.1.15 or higher/ NET3.038 5 * 6 * This module: 7 * This module is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 10 * 2 of the License, or (at your option) any later version. 11 * 12 * This is a "pseudo" network driver to allow LAPB over Ethernet. 13 * 14 * This driver can use any ethernet destination address, and can be 15 * limited to accept frames from one dedicated ethernet card only. 16 * 17 * History 18 * LAPBETH 001 Jonathan Naylor Cloned from bpqether.c 19 * 2000-10-29 Henner Eisen lapb_data_indication() return status. 20 * 2000-11-14 Henner Eisen dev_hold/put, NETDEV_GOING_DOWN support 21 */ 22 23 #include <linux/errno.h> 24 #include <linux/types.h> 25 #include <linux/socket.h> 26 #include <linux/in.h> 27 #include <linux/kernel.h> 28 #include <linux/string.h> 29 #include <linux/net.h> 30 #include <linux/inet.h> 31 #include <linux/netdevice.h> 32 #include <linux/if_arp.h> 33 #include <linux/skbuff.h> 34 #include <net/sock.h> 35 #include <asm/system.h> 36 #include <asm/uaccess.h> 37 #include <linux/mm.h> 38 #include <linux/interrupt.h> 39 #include <linux/notifier.h> 40 #include <linux/stat.h> 41 #include <linux/netfilter.h> 42 #include <linux/module.h> 43 #include <linux/lapb.h> 44 #include <linux/init.h> 45 46 #include <net/x25device.h> 47 48 static char bcast_addr[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF }; 49 50 /* If this number is made larger, check that the temporary string buffer 51 * in lapbeth_new_device is large enough to store the probe device name.*/ 52 #define MAXLAPBDEV 100 53 54 struct lapbethdev { 55 struct list_head node; 56 struct net_device *ethdev; /* link to ethernet device */ 57 struct net_device *axdev; /* lapbeth device (lapb#) */ 58 }; 59 60 static LIST_HEAD(lapbeth_devices); 61 62 /* ------------------------------------------------------------------------ */ 63 64 /* 65 * Get the LAPB device for the ethernet device 66 */ 67 static struct lapbethdev *lapbeth_get_x25_dev(struct net_device *dev) 68 { 69 struct lapbethdev *lapbeth; 70 71 list_for_each_entry_rcu(lapbeth, &lapbeth_devices, node) { 72 if (lapbeth->ethdev == dev) 73 return lapbeth; 74 } 75 return NULL; 76 } 77 78 static __inline__ int dev_is_ethdev(struct net_device *dev) 79 { 80 return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5); 81 } 82 83 /* ------------------------------------------------------------------------ */ 84 85 /* 86 * Receive a LAPB frame via an ethernet interface. 87 */ 88 static int lapbeth_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev) 89 { 90 int len, err; 91 struct lapbethdev *lapbeth; 92 93 if (dev_net(dev) != &init_net) 94 goto drop; 95 96 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) 97 return NET_RX_DROP; 98 99 if (!pskb_may_pull(skb, 2)) 100 goto drop; 101 102 rcu_read_lock(); 103 lapbeth = lapbeth_get_x25_dev(dev); 104 if (!lapbeth) 105 goto drop_unlock; 106 if (!netif_running(lapbeth->axdev)) 107 goto drop_unlock; 108 109 len = skb->data[0] + skb->data[1] * 256; 110 dev->stats.rx_packets++; 111 dev->stats.rx_bytes += len; 112 113 skb_pull(skb, 2); /* Remove the length bytes */ 114 skb_trim(skb, len); /* Set the length of the data */ 115 116 if ((err = lapb_data_received(lapbeth->axdev, skb)) != LAPB_OK) { 117 printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err); 118 goto drop_unlock; 119 } 120 out: 121 rcu_read_unlock(); 122 return 0; 123 drop_unlock: 124 kfree_skb(skb); 125 goto out; 126 drop: 127 kfree_skb(skb); 128 return 0; 129 } 130 131 static int lapbeth_data_indication(struct net_device *dev, struct sk_buff *skb) 132 { 133 unsigned char *ptr; 134 135 skb_push(skb, 1); 136 137 if (skb_cow(skb, 1)) 138 return NET_RX_DROP; 139 140 ptr = skb->data; 141 *ptr = 0x00; 142 143 skb->protocol = x25_type_trans(skb, dev); 144 return netif_rx(skb); 145 } 146 147 /* 148 * Send a LAPB frame via an ethernet interface 149 */ 150 static netdev_tx_t lapbeth_xmit(struct sk_buff *skb, 151 struct net_device *dev) 152 { 153 int err; 154 155 /* 156 * Just to be *really* sure not to send anything if the interface 157 * is down, the ethernet device may have gone. 158 */ 159 if (!netif_running(dev)) 160 goto drop; 161 162 switch (skb->data[0]) { 163 case 0x00: 164 break; 165 case 0x01: 166 if ((err = lapb_connect_request(dev)) != LAPB_OK) 167 printk(KERN_ERR "lapbeth: lapb_connect_request " 168 "error: %d\n", err); 169 goto drop; 170 case 0x02: 171 if ((err = lapb_disconnect_request(dev)) != LAPB_OK) 172 printk(KERN_ERR "lapbeth: lapb_disconnect_request " 173 "err: %d\n", err); 174 /* Fall thru */ 175 default: 176 goto drop; 177 } 178 179 skb_pull(skb, 1); 180 181 if ((err = lapb_data_request(dev, skb)) != LAPB_OK) { 182 printk(KERN_ERR "lapbeth: lapb_data_request error - %d\n", err); 183 goto drop; 184 } 185 out: 186 return NETDEV_TX_OK; 187 drop: 188 kfree_skb(skb); 189 goto out; 190 } 191 192 static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb) 193 { 194 struct lapbethdev *lapbeth = netdev_priv(ndev); 195 unsigned char *ptr; 196 struct net_device *dev; 197 int size = skb->len; 198 199 skb->protocol = htons(ETH_P_X25); 200 201 ptr = skb_push(skb, 2); 202 203 *ptr++ = size % 256; 204 *ptr++ = size / 256; 205 206 ndev->stats.tx_packets++; 207 ndev->stats.tx_bytes += size; 208 209 skb->dev = dev = lapbeth->ethdev; 210 211 dev_hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0); 212 213 dev_queue_xmit(skb); 214 } 215 216 static void lapbeth_connected(struct net_device *dev, int reason) 217 { 218 unsigned char *ptr; 219 struct sk_buff *skb = dev_alloc_skb(1); 220 221 if (!skb) { 222 printk(KERN_ERR "lapbeth: out of memory\n"); 223 return; 224 } 225 226 ptr = skb_put(skb, 1); 227 *ptr = 0x01; 228 229 skb->protocol = x25_type_trans(skb, dev); 230 netif_rx(skb); 231 } 232 233 static void lapbeth_disconnected(struct net_device *dev, int reason) 234 { 235 unsigned char *ptr; 236 struct sk_buff *skb = dev_alloc_skb(1); 237 238 if (!skb) { 239 printk(KERN_ERR "lapbeth: out of memory\n"); 240 return; 241 } 242 243 ptr = skb_put(skb, 1); 244 *ptr = 0x02; 245 246 skb->protocol = x25_type_trans(skb, dev); 247 netif_rx(skb); 248 } 249 250 /* 251 * Set AX.25 callsign 252 */ 253 static int lapbeth_set_mac_address(struct net_device *dev, void *addr) 254 { 255 struct sockaddr *sa = addr; 256 memcpy(dev->dev_addr, sa->sa_data, dev->addr_len); 257 return 0; 258 } 259 260 261 static struct lapb_register_struct lapbeth_callbacks = { 262 .connect_confirmation = lapbeth_connected, 263 .connect_indication = lapbeth_connected, 264 .disconnect_confirmation = lapbeth_disconnected, 265 .disconnect_indication = lapbeth_disconnected, 266 .data_indication = lapbeth_data_indication, 267 .data_transmit = lapbeth_data_transmit, 268 269 }; 270 271 /* 272 * open/close a device 273 */ 274 static int lapbeth_open(struct net_device *dev) 275 { 276 int err; 277 278 if ((err = lapb_register(dev, &lapbeth_callbacks)) != LAPB_OK) { 279 printk(KERN_ERR "lapbeth: lapb_register error - %d\n", err); 280 return -ENODEV; 281 } 282 283 netif_start_queue(dev); 284 return 0; 285 } 286 287 static int lapbeth_close(struct net_device *dev) 288 { 289 int err; 290 291 netif_stop_queue(dev); 292 293 if ((err = lapb_unregister(dev)) != LAPB_OK) 294 printk(KERN_ERR "lapbeth: lapb_unregister error - %d\n", err); 295 296 return 0; 297 } 298 299 /* ------------------------------------------------------------------------ */ 300 301 static const struct net_device_ops lapbeth_netdev_ops = { 302 .ndo_open = lapbeth_open, 303 .ndo_stop = lapbeth_close, 304 .ndo_start_xmit = lapbeth_xmit, 305 .ndo_set_mac_address = lapbeth_set_mac_address, 306 }; 307 308 static void lapbeth_setup(struct net_device *dev) 309 { 310 dev->netdev_ops = &lapbeth_netdev_ops; 311 dev->destructor = free_netdev; 312 dev->type = ARPHRD_X25; 313 dev->hard_header_len = 3; 314 dev->mtu = 1000; 315 dev->addr_len = 0; 316 } 317 318 /* 319 * Setup a new device. 320 */ 321 static int lapbeth_new_device(struct net_device *dev) 322 { 323 struct net_device *ndev; 324 struct lapbethdev *lapbeth; 325 int rc = -ENOMEM; 326 327 ASSERT_RTNL(); 328 329 ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d", 330 lapbeth_setup); 331 if (!ndev) 332 goto out; 333 334 lapbeth = netdev_priv(ndev); 335 lapbeth->axdev = ndev; 336 337 dev_hold(dev); 338 lapbeth->ethdev = dev; 339 340 rc = dev_alloc_name(ndev, ndev->name); 341 if (rc < 0) 342 goto fail; 343 344 rc = -EIO; 345 if (register_netdevice(ndev)) 346 goto fail; 347 348 list_add_rcu(&lapbeth->node, &lapbeth_devices); 349 rc = 0; 350 out: 351 return rc; 352 fail: 353 dev_put(dev); 354 free_netdev(ndev); 355 kfree(lapbeth); 356 goto out; 357 } 358 359 /* 360 * Free a lapb network device. 361 */ 362 static void lapbeth_free_device(struct lapbethdev *lapbeth) 363 { 364 dev_put(lapbeth->ethdev); 365 list_del_rcu(&lapbeth->node); 366 unregister_netdevice(lapbeth->axdev); 367 } 368 369 /* 370 * Handle device status changes. 371 * 372 * Called from notifier with RTNL held. 373 */ 374 static int lapbeth_device_event(struct notifier_block *this, 375 unsigned long event, void *ptr) 376 { 377 struct lapbethdev *lapbeth; 378 struct net_device *dev = ptr; 379 380 if (dev_net(dev) != &init_net) 381 return NOTIFY_DONE; 382 383 if (!dev_is_ethdev(dev)) 384 return NOTIFY_DONE; 385 386 switch (event) { 387 case NETDEV_UP: 388 /* New ethernet device -> new LAPB interface */ 389 if (lapbeth_get_x25_dev(dev) == NULL) 390 lapbeth_new_device(dev); 391 break; 392 case NETDEV_DOWN: 393 /* ethernet device closed -> close LAPB interface */ 394 lapbeth = lapbeth_get_x25_dev(dev); 395 if (lapbeth) 396 dev_close(lapbeth->axdev); 397 break; 398 case NETDEV_UNREGISTER: 399 /* ethernet device disappears -> remove LAPB interface */ 400 lapbeth = lapbeth_get_x25_dev(dev); 401 if (lapbeth) 402 lapbeth_free_device(lapbeth); 403 break; 404 } 405 406 return NOTIFY_DONE; 407 } 408 409 /* ------------------------------------------------------------------------ */ 410 411 static struct packet_type lapbeth_packet_type __read_mostly = { 412 .type = cpu_to_be16(ETH_P_DEC), 413 .func = lapbeth_rcv, 414 }; 415 416 static struct notifier_block lapbeth_dev_notifier = { 417 .notifier_call = lapbeth_device_event, 418 }; 419 420 static const char banner[] __initconst = 421 KERN_INFO "LAPB Ethernet driver version 0.02\n"; 422 423 static int __init lapbeth_init_driver(void) 424 { 425 dev_add_pack(&lapbeth_packet_type); 426 427 register_netdevice_notifier(&lapbeth_dev_notifier); 428 429 printk(banner); 430 431 return 0; 432 } 433 module_init(lapbeth_init_driver); 434 435 static void __exit lapbeth_cleanup_driver(void) 436 { 437 struct lapbethdev *lapbeth; 438 struct list_head *entry, *tmp; 439 440 dev_remove_pack(&lapbeth_packet_type); 441 unregister_netdevice_notifier(&lapbeth_dev_notifier); 442 443 rtnl_lock(); 444 list_for_each_safe(entry, tmp, &lapbeth_devices) { 445 lapbeth = list_entry(entry, struct lapbethdev, node); 446 447 dev_put(lapbeth->ethdev); 448 unregister_netdevice(lapbeth->axdev); 449 } 450 rtnl_unlock(); 451 } 452 module_exit(lapbeth_cleanup_driver); 453 454 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>"); 455 MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver"); 456 MODULE_LICENSE("GPL"); 457